how to make uipageviewcontroller go in circles - ios

Question

I'm having a UIPageViewController that shows different pages. The current behaviour is that it stops scrolling when I reached the last page. What I now want to achieve is that when on the last page and scrolling right, it goes to the first page. When at the first page, go to the last page when scrolling left. So basically let the PageViewController show the pages in circles. My first approach works quite well while having more than one page, or starting with one single page:
- (UIViewController*) pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(TMCollectionViewController *)viewController
{
if((viewController.pageIndex) >= 1)
{
return _viewControllers[viewController.pageIndex - 1];
}
else
{
if ([_viewControllers count] == 1) {
return nil;
}
return [_viewControllers objectAtIndex:[_viewControllers count]-1];
}
}
But when I remove the pages so that only one is left, it still remembers either the before or after page, and shows it accordingly. Even though there is only one page left in the array. Any help is highly appreciated.

Answer 1

You can implement it as
When you are on 1st index and swipe left make its index = total count of pages
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
NSUInteger index = ((PageContentViewController*) viewController).pageIndex;
if ((index == 0) || (index == NSNotFound)) {
index = self.pageTitles.count;
}
index--;
return [_viewControllers objectAtIndex:index];
}
When you are on last index set it to zero index
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
NSUInteger index = ((PageContentViewController*) viewController).pageIndex;
if (index == NSNotFound) {
return nil;
}
index++;
if (index == [self.pageTitles count]) {
index = 0;
}
return [_viewControllers objectAtIndex:index];
}

Answer 2

Thanks, #Roshni
Swift 2 - Roshni's solution
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
var index: Int = (viewController as! PageContentViewController).index
if index == 0 || index == NSNotFound {
index = self.pageTitles.count
}
index--
return viewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
var index: Int = (viewController as! PageContentViewController).index
if index == NSNotFound {
return nil
}
index++
if index == self.pageTitles.count {
index = 0
}
return viewControllerAtIndex(index)
}

Answer 3

here is sample, I did for circular pagination
I was using Using UIPageViewController to create a content slider (Objective-C/Swift) article but thanks to #Tom Calmon and #Roshani now I am able to achieve my desired result on Swift 2.2
class PageHomeViewController: UIViewController , UIPageViewControllerDataSource{
// MARK: - Variables
private var pageViewController: UIPageViewController?
// Initialize it right away here
private let contentImages = ["nature_pic_1.png",
"nature_pic_2.png",
"nature_pic_3.png",
"nature_pic_4.png"];
//MARK: - View controller life cycle methods
override func viewDidLoad() {
super.viewDidLoad()
createPageViewController()
setupPageControl()
}
//MARK: - Create and start page view controller
private func createPageViewController() {
let pageController = self.storyboard!.instantiateViewControllerWithIdentifier("PageViewController") as! UIPageViewController
pageController.dataSource = self
if contentImages.count > 0 {
let firstController = getItemController(0)!
let startingViewControllers: NSArray = [firstController]
pageController.setViewControllers(startingViewControllers as? [UIViewController], direction: UIPageViewControllerNavigationDirection.Forward, animated: false, completion: nil)
}
pageViewController = pageController
addChildViewController(pageViewController!)
self.view.addSubview(pageViewController!.view)
pageViewController!.didMoveToParentViewController(self)
}
private func setupPageControl() {
let appearance = UIPageControl.appearance()
appearance.pageIndicatorTintColor = UIColor.grayColor()
appearance.currentPageIndicatorTintColor = UIColor.whiteColor()
appearance.backgroundColor = UIColor.darkGrayColor()
}
// MARK: - UIPageViewControllerDataSource
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
var index: Int = (viewController as! PageContentViewController).itemIndex
if index == 0 || index == NSNotFound {
index = contentImages.count
}
index -= 1
return getItemController(index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController?{
var index: Int = (viewController as! PageContentViewController).itemIndex
if index == NSNotFound {return nil}
index += 1
if index == contentImages.count {index = 0}
return getItemController(index)
}
private func getItemController(itemIndex: Int) -> PageContentViewController? {
if itemIndex < contentImages.count {
let pageItemController = self.storyboard!.instantiateViewControllerWithIdentifier("PageContentViewController") as! PageContentViewController
pageItemController.itemIndex = itemIndex
pageItemController.imageName = contentImages[itemIndex]
return pageItemController
}
return nil
}
// MARK: - Page Indicator
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
return contentImages.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
return 0
}
}
Hope this will help out there someone , someday!!